318 lines
11 KiB
C++
318 lines
11 KiB
C++
/**
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* @file channel.h
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* @author Adam Wonak (https://github.com/awonak/)
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* @brief Alt firmware version of Gravity by Sitka Instruments.
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* @version 2.0.1
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* @date 2025-07-04
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*
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* @copyright MIT - (c) 2025 - Adam Wonak - adam.wonak@gmail.com
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*
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*/
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#ifndef CHANNEL_H
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#define CHANNEL_H
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#include <Arduino.h>
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#include <libGravity.h>
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#include "euclidean.h"
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// Enums for CV Mod destination
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enum CvDestination : uint8_t {
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CV_DEST_NONE,
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CV_DEST_MOD,
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CV_DEST_PROB,
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CV_DEST_DUTY,
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CV_DEST_OFFSET,
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CV_DEST_SWING,
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CV_DEST_EUC_STEPS,
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CV_DEST_EUC_HITS,
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CV_DEST_LAST,
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};
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static const byte MOD_CHOICE_SIZE = 25;
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// Negative numbers are multipliers, positive are divisors.
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static const int CLOCK_MOD[MOD_CHOICE_SIZE] PROGMEM = {
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// Divisors
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128, 64, 32, 24, 16, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2,
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// Internal Clock Unity (quarter note)
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1,
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// Multipliers
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-2, -3, -4, -6, -8, -12, -16, -24};
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// This represents the number of clock pulses for a 96 PPQN clock source
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// that match the above div/mult mods.
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static const int CLOCK_MOD_PULSES[MOD_CHOICE_SIZE] PROGMEM = {
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// Divisor Pulses (96 * X)
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12288, 6144, 3072, 2304, 1536, 1152, 1056, 960, 864, 768, 672, 576, 480, 384, 288, 192,
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// Internal Clock Pulses
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96,
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// Multiplier Pulses (96 / X)
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48, 32, 24, 16, 12, 8, 6, 4};
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static const byte DEFAULT_CLOCK_MOD_INDEX = 16; // x1 or 96 PPQN.
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static const byte PULSE_PPQN_24_CLOCK_MOD_INDEX = MOD_CHOICE_SIZE - 1;
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static const byte PULSE_PPQN_4_CLOCK_MOD_INDEX = MOD_CHOICE_SIZE - 6;
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static const byte PULSE_PPQN_1_CLOCK_MOD_INDEX = MOD_CHOICE_SIZE - 9;
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class Channel {
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public:
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Channel() {
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Init();
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}
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void Init() {
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// Reset base values to their defaults
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base_clock_mod_index = DEFAULT_CLOCK_MOD_INDEX;
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base_probability = 100;
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base_duty_cycle = 50;
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base_offset = 0;
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base_swing = 50;
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base_euc_steps = 1;
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base_euc_hits = 1;
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cvmod_clock_mod_index = base_clock_mod_index;
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cvmod_probability = base_probability;
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cvmod_duty_cycle = base_duty_cycle;
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cvmod_offset = base_offset;
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cvmod_swing = base_swing;
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cv1_dest = CV_DEST_NONE;
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cv2_dest = CV_DEST_NONE;
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pattern.Init(DEFAULT_PATTERN);
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// Calcule the clock mod pulses on init.
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_recalculatePulses();
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}
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// Setters (Set the BASE value)
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void setClockMod(int index) {
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base_clock_mod_index = constrain(index, 0, MOD_CHOICE_SIZE - 1);
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if (!isCvModActive()) {
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cvmod_clock_mod_index = base_clock_mod_index;
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_recalculatePulses();
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}
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}
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void setProbability(int prob) {
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base_probability = constrain(prob, 0, 100);
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if (!isCvModActive()) {
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cvmod_probability = base_probability;
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_recalculatePulses();
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}
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}
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void setDutyCycle(int duty) {
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base_duty_cycle = constrain(duty, 1, 99);
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if (!isCvModActive()) {
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cvmod_duty_cycle = base_duty_cycle;
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_recalculatePulses();
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}
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}
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void setOffset(int off) {
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base_offset = constrain(off, 0, 99);
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if (!isCvModActive()) {
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cvmod_offset = base_offset;
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_recalculatePulses();
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}
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}
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void setSwing(int val) {
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base_swing = constrain(val, 50, 95);
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if (!isCvModActive()) {
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cvmod_swing = base_swing;
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_recalculatePulses();
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}
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}
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// Euclidean
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void setSteps(int val) {
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base_euc_steps = constrain(val, 1, MAX_PATTERN_LEN);
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if (cv1_dest != CV_DEST_EUC_STEPS && cv2_dest != CV_DEST_EUC_STEPS) {
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pattern.SetSteps(val);
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}
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}
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void setHits(int val) {
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base_euc_hits = constrain(val, 1, base_euc_steps);
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if (cv1_dest != CV_DEST_EUC_HITS && cv2_dest != CV_DEST_EUC_HITS) {
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pattern.SetHits(val);
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}
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}
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void setCv1Dest(CvDestination dest) { cv1_dest = dest; }
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void setCv2Dest(CvDestination dest) { cv2_dest = dest; }
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CvDestination getCv1Dest() const { return cv1_dest; }
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CvDestination getCv2Dest() const { return cv2_dest; }
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// Getters (Get the BASE value for editing or cv modded value for display)
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int getProbability(bool withCvMod = false) const { return withCvMod ? cvmod_probability : base_probability; }
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int getDutyCycle(bool withCvMod = false) const { return withCvMod ? cvmod_duty_cycle : base_duty_cycle; }
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int getOffset(bool withCvMod = false) const { return withCvMod ? cvmod_offset : base_offset; }
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int getSwing(bool withCvMod = false) const { return withCvMod ? cvmod_swing : base_swing; }
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int getClockMod(bool withCvMod = false) const { return pgm_read_word_near(&CLOCK_MOD[getClockModIndex(withCvMod)]); }
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int getClockModIndex(bool withCvMod = false) const { return withCvMod ? cvmod_clock_mod_index : base_clock_mod_index; }
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bool isCvModActive() const { return cv1_dest != CV_DEST_NONE || cv2_dest != CV_DEST_NONE; }
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byte getSteps(bool withCvMod = false) const { return withCvMod ? pattern.GetSteps() : base_euc_steps; }
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byte getHits(bool withCvMod = false) const { return withCvMod ? pattern.GetHits() : base_euc_hits; }
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void toggleMute() { mute = !mute; }
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/**
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* @brief Processes a clock tick and determines if the output should be high or low.
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* Note: this method is called from an ISR and must be kept as simple as possible.
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* @param tick The current clock tick count.
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* @param output The output object to be modified.
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*/
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void processClockTick(uint32_t tick, DigitalOutput& output) {
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// Mute check
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if (mute) {
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output.Low();
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return;
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}
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const uint16_t mod_pulses = pgm_read_word_near(&CLOCK_MOD_PULSES[cvmod_clock_mod_index]);
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// Conditionally apply swing on down beats.
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uint16_t swing_pulses = 0;
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if (_swing_pulse_amount > 0 && (tick / mod_pulses) % 2 == 1) {
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swing_pulses = _swing_pulse_amount;
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}
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// Duty cycle high check logic
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const uint32_t current_tick_offset = tick + _offset_pulses + swing_pulses;
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if (!output.On()) {
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// Step check
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if (current_tick_offset % mod_pulses == 0) {
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bool hit = cvmod_probability >= random(0, 100);
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// Euclidean rhythm hit check
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switch (pattern.NextStep()) {
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case Pattern::REST: // Rest when active or fall back to probability
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hit = false;
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break;
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case Pattern::HIT: // Hit if probability is true
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hit &= true;
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break;
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}
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if (hit) {
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output.High();
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}
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}
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}
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// Duty cycle low check
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const uint32_t duty_cycle_end_tick = tick + _duty_pulses + _offset_pulses + swing_pulses;
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if (duty_cycle_end_tick % mod_pulses == 0) {
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output.Low();
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}
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}
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/**
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* @brief Calculate and store cv modded values using bipolar mapping.
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* Default to base value if not the current CV destination.
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*
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* @param cv1_val analog input reading for cv1
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* @param cv2_val analog input reading for cv2
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*
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*/
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void applyCvMod(int cv1_val, int cv2_val) {
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// Note: This is optimized for cpu performance. This method is called
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// from the main loop and stores the cv mod values. This reduces CPU
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// cycles inside the internal clock interrupt, which is preferrable.
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// However, if RAM usage grows too much, we have an opportunity to
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// refactor this to store just the CV read values, and calculate the
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// cv mod value per channel inside the getter methods by passing cv
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// values. This would reduce RAM usage, but would introduce a
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// significant CPU cost, which may have undesirable performance issues.
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if (!isCvModActive()) {
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cvmod_clock_mod_index = base_clock_mod_index;
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cvmod_probability = base_clock_mod_index;
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cvmod_duty_cycle = base_clock_mod_index;
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cvmod_offset = base_clock_mod_index;
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cvmod_swing = base_clock_mod_index;
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return;
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}
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int dest_mod = _calculateMod(CV_DEST_MOD, cv1_val, cv2_val, -(MOD_CHOICE_SIZE / 2), MOD_CHOICE_SIZE / 2);
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cvmod_clock_mod_index = constrain(base_clock_mod_index + dest_mod, 0, MOD_CHOICE_SIZE - 1);
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int prob_mod = _calculateMod(CV_DEST_PROB, cv1_val, cv2_val, -50, 50);
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cvmod_probability = constrain(base_probability + prob_mod, 0, 100);
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int duty_mod = _calculateMod(CV_DEST_DUTY, cv1_val, cv2_val, -50, 50);
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cvmod_duty_cycle = constrain(base_duty_cycle + duty_mod, 1, 99);
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int offset_mod = _calculateMod(CV_DEST_OFFSET, cv1_val, cv2_val, -50, 50);
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cvmod_offset = constrain(base_offset + offset_mod, 0, 99);
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int swing_mod = _calculateMod(CV_DEST_SWING, cv1_val, cv2_val, -25, 25);
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cvmod_swing = constrain(base_swing + swing_mod, 50, 95);
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int step_mod = _calculateMod(CV_DEST_EUC_STEPS, cv1_val, cv2_val, 0, MAX_PATTERN_LEN);
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pattern.SetSteps(base_euc_steps + step_mod);
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int hit_mod = _calculateMod(CV_DEST_EUC_HITS, cv1_val, cv2_val, 0, pattern.GetSteps());
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pattern.SetHits(base_euc_hits + hit_mod);
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// After all cvmod values are updated, recalculate clock pulse modifiers.
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_recalculatePulses();
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}
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private:
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int _calculateMod(CvDestination dest, int cv1_val, int cv2_val, int min_range, int max_range) {
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int mod1 = (cv1_dest == dest) ? map(cv1_val, -512, 512, min_range, max_range) : 0;
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int mod2 = (cv2_dest == dest) ? map(cv2_val, -512, 512, min_range, max_range) : 0;
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return mod1 + mod2;
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}
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void _recalculatePulses() {
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const uint16_t mod_pulses = pgm_read_word_near(&CLOCK_MOD_PULSES[cvmod_clock_mod_index]);
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_duty_pulses = max((long)((mod_pulses * (100L - cvmod_duty_cycle)) / 100L), 1L);
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_offset_pulses = (long)((mod_pulses * (100L - cvmod_offset)) / 100L);
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// Calculate the down beat swing amount.
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if (cvmod_swing > 50) {
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int shifted_swing = cvmod_swing - 50;
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_swing_pulse_amount = (long)((mod_pulses * (100L - shifted_swing)) / 100L);
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} else {
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_swing_pulse_amount = 0;
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}
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}
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// User-settable base values.
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byte base_clock_mod_index;
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byte base_probability;
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byte base_duty_cycle;
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byte base_offset;
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byte base_swing;
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byte base_euc_steps;
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byte base_euc_hits;
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// Base value with cv mod applied.
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byte cvmod_clock_mod_index;
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byte cvmod_probability;
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byte cvmod_duty_cycle;
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byte cvmod_offset;
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byte cvmod_swing;
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// CV mod configuration
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CvDestination cv1_dest;
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CvDestination cv2_dest;
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// Euclidean pattern
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Pattern pattern;
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// Mute channel flag
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bool mute;
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// Pre-calculated pulse values for ISR performance
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uint16_t _duty_pulses;
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uint16_t _offset_pulses;
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uint16_t _swing_pulse_amount;
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};
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#endif // CHANNEL_H
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